This invention relates to steel making and has particular relationship to continuous casting. In continuous casting each of one or more streams of molten metal flow into a chill mold having a cavity where the metal solidifies. The metal solidifies about a starter stool which advances the solidified mass and the strip attached to it to pinch rolls that advance the strip to the cutting shears. Typical continuous-casting apparatus is shown in Cashdollar U.S. Pat. No. 3,754,590.
The mold is a water-cooled structure of substantial cost. The walls bounding the opening in the mold through which the molten metal flows have holes for injecting lubricant to lubricate the walls of the opening and the mold cavity. If no protective cover were interposed between the walls of the opening in the mold and the stream of molten metal, molten metal would in a short time adhere to the walls of the mold damaging the mold beyond repair or demanding time-consuming and costly operations by a lancer to burn off the adhered metal. Also, hangers solidified from the attached molten metal would extend between the mold and the mass moving away from the mold. Since this mass is still unsolidified in the center, the hangers would tear the solidified mass. In addition, the lubricant holes would become clogged, depriving the walls of the mold of lubricant. To protect the mold, a cover is provided. In accordance with the teachings of the prior art, this cover has an opening, aligned with the opening in the mold, whose inner and outer boundaries have sharp corners similar to the corners of the opening in the mold which the cover overlies.
In practice these prior-art covers proved unsatisfactory. There is splatter build-up on the cover from the molten metal. Hangers are still produced and they tear the skin of the molded metal resulting in break outs and costly damage. Frequently it is necessary to restart the continuous-casting line. Considerable time and cost for replacing molds and lancing is still demanded. The lubricant-injection holes still become clogged and the flow of lubricant is otherwise obstructed.
It is an object of this invention to overcome the above-described deficiencies of the prior art and to provide continuous-casting apparatus whose molds shall be effectively protected from molten metal which flows into the molds and the formation of hangers and the tearing of the skin of the molded metal together with the costs incident to the adhesion of metal from the molten mass shall be precluded. It is also an object of this invention to provide a cover for the mold of continuous-casting apparatus with which the above-described deficiencies of the prior art shall be overcome.